I've broken about 4 Chinook's, all near the head and all in about 9 or 10 months, I put it down to work hardening (flexing). Having said that, I got the best runs out of the Chinooks, compared to others.
I now have a Chinook carbon, and for me it's proven to be cheaper in the long run, but I only sail ocean with no waves (FNQ).
Just my 2c